Two helicopters from Auckland and another from Northland, airlifted the worst injured to Whangārei Hospital. Five St John ambulances responded from across the district.
The driver of the Odyssey, 32, was initially taken to Bay of Islands Hospital with moderate injuries but was later also flown to Whangārei. Le Comte said inquiries were continuing.
''At this stage it appears one of the vehicles has lost control in the wet and crossed the centreline into the path of the other vehicle.''
A woman told the NZ Herald the northbound vehicle had overtaken her car at speed moments earlier. She heard the crash then saw the aftermath as she rounded a corner on SH1. It had been raining and the road was slippery, she said.
Traffic was diverted via Mangakahia Rd/SH15 for about four hours with some motorists choosing to wait in Kawakawa or take Ruapekapeka Rd instead.
Later, about 8.30pm, Le Comte said a foreign national was driving an SUV south on SH10, about 1km south of the Matauri Bay turnoff, when he pulled out to overtake another vehicle and collided head-on with a northbound ute.
The SUV driver's wife, who was in the front passenger seat, was critically injured. She was taken by ambulance to Kerikeri airport then flown to Whangārei Hospital by the Northland Rescue Helicopter. The driver and their son received moderate injuries.
The driver had been summonsed to appear in the Kaikohe District Court this Wednesday on an initial charge of careless driving causing injury. It is believed the visitors had been due to leave New Zealand next weekend.
A Northland man and woman in the ute received moderate injuries and were treated at the scene. However, the woman was taken to Whangārei Hospital and underwent surgery when her condition deteriorated later that night.